Two Polaroids are placed in such a way that their axes make an angle of \( 60^\circ \) with each other. If an unpolarized light is incident on a system of these Polaroids, the fraction of transmitted light to the incident light will be
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 1/8
An unpolarised beam loses half its intensity at the first polaroid, and the light that comes out is plane polarised. The second polaroid then follows Malus's law.
\( \displaystyle I_1 = \frac{I_0}{2} \qquad I_2 = I_1\cos^{2}\theta \)
\( \displaystyle I_2 = \frac{I_0}{2}\cos^{2}60^\circ = \frac{I_0}{2} \times \frac{1}{4} = \frac{I_0}{8} \)
So the fraction transmitted is \( 1/8 \).